How to nicely tell someone you don't want to hang out with them?

[Goku]

It doesnt matter anyway. Guy is 10 years old.

Yeah, like other people have said, I'm not 10.

[pcmaster]

Well you look younger. At least in brains.

[Goku]

Thanks for the help everyone. I told her that I'm not comfortable hanging out with her now that I am dating ___.
@michelle23 yeah I guess you're right. I thought it would be ok since it was just hanging out, but I see your point. I'm new to the whole dating thing.
@searock same thing I said to michelle23

[Goku]

Well you look younger. At least in brains.

Right... because me asking a question on a forum means, I don't have any brains. Right, well you've asked some questions here before, so you could technically say the same thing about you then, right?
Like I have said to others on forums I hate to get into arguments with people on the internet. I wont reply if you say something again, UNLESS it actually matters.

[pcmaster]

Its actually compliment so chill out and be happy. Its great to have a young mind so you can absorb better all the BS on forums.